Abstract
It is well known that only a small additions of boron remarkably improve hardenability of steel. Therefore, for the purpose of saving mineral resources such as nickel and molybdenum, substituting boron steel for low alloy structural steel is now being desired.
However, its compound in steel, analytic value and effect on the hardenability change complicatedly by thermal history and their correlation hasn't been clarified yet.
This paper discusses thermodynamically the behavior of boron in steel containing Al, Ti, N, C and conducts formulae for the calculation of matrix solved boron in steel which is heated to austenite temperature range.
Calculated values of matrix solved boron agree well with analyzed acid soluble boron and they also correspond well to Jominy distances to 50% martensite.
